Quantifying the effects of anagenetic and cladogenetic evolution

TL;DR

This paper introduces a comprehensive framework to quantify phenotypic change in evolution, distinguishing between gradual and speciation-associated changes, with applications to Hominoid body size and mathematical derivations for evolutionary tree properties.

Contribution

It develops a general model combining anagenetic and cladogenetic evolution, providing formulas for parameter estimation and properties of evolutionary trees.

Findings

Quantified effects of speciation-related phenotypic change

Derived formulas for lineage and common ancestor distances

Applied model to Hominoid body size evolution

Abstract

An ongoing debate in evolutionary biology is whether phenotypic change occurs predominantly around the time of speciation or whether it instead accumulates gradually over time. In this work I propose a general framework incorporating both types of change, quantify the effects of speciational change via the correlation between species and attribute the proportion of change to each type. I discuss results of parameter estimation of Hominoid body size in this light. I derive mathematical formulae related to this problem, the probability generating functions of the number of speciation events along a randomly drawn lineage and from the most recent common ancestor of two randomly chosen tip species for a conditioned Yule tree. Additionally I obtain in closed form the variance of the distance from the root to the most recent common ancestor of two randomly chosen tip species.